Saeed, Ahmad (2002) INHERITANCE OF SOME CHARACTERS IN RA (ABELMOSCHUS ESCULENTUS L. MODENCH) UNDER DROUGHT CONDITIONS. PhD thesis, Sindh Agriculture University, Tando Jam.
The drought related studies of okra (Ablmoschus esculentus L. Moench) were carried out in field conditions, in an experiment, the most sensitive growth stage to drought in five okra varieties and one strain was studied, For this purpose the drought was given at various growth stages. It was concluded that the flowering and podding stage was the most sensitive to drought, as at this stage maximum reduction in yield and yield components was found. The inheritance of characteristics of okra under drought was studied. For this purpose 6x6 diallel was carried out to study gene action, general combining ability (GCA), specific it combining ability (SCA) and heterosis under both normal and drought conditions. On the basis' of the highest mean performance, the highest general combining ability and moderate to high specific combining ability for fresh fruit yield per plant, number of pods per plant and seed yield per plant, three crosses were selected under drought conditions, The six generations (P1,P2, F1,F2,BC1 & BC2) of the three crosses were generated to study heterosis, inbreeding depression, dominance, heritability, genetic advance and gene action under both normal and water stress conditions, Positive heterosis and inbreeding depression were observed in the crosses for water content of fruit, fresh fruit yield per plant, number of pods per plant. Number of branches per plant, 100 seed weight and seed yield per plant under both normal and stress conditions. On over all basis the crosses showed reduction in heterosis and inbreeding depression due to water stress, However, progress in these parameters due to stress was also observed for fresh fruit yield per plant, number of pods per plant, diameter of fruit and seed yield per plant, Most of the crosses showed partial and over dominance under both conditions except for number of branches per plant, where only one cross showed complete dominance under normal conditions. Water stress caused reduction in heritability and genetic advance but progress due to stress was observed in some crosses for days to 50% flowering, water content of fruit. 100 seed: weight, relative growth rate of fruit, fresh fruit yield per plant, number of pods per plant. Additive variance components were decreased by giving stress for fresh fruit yield per plant, seed yield' per plant and increased for number of branches per plant. However additive variance was not affected by water stress for number of pods per plant, Additive genetic effects for height of first flowering node, days to maturity, plant height and number of seeds per pod were observed under normal conditions. On the other hand the crosses under stress conditions showed additive effects for days to first flowering and days to 50% flowering. The crosses exhibited additive genetic effects under both conditions for relative growth rate of fruit and number of branches per plant. Dominance was observed for fresh fruit yield per plant under normal conditions and for number of seeds per pod, relative growth rate of fruit and days to 50% flowering under stress conditions. In both normal and stress conditions, none of the genetic effects and interaction component appeared to be involved in 'all the crosses for the expression of seed yield per plant, t number of pods per plant and 100 seed weight. The results for these characters show that most of the variations were due to environment.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Okra (Abelmoschus Esculentus L. Moench), Drought conditions, Flowering, Podding stage, Reduction in yield, Yield components, Gene action, General combining ability GCA, Specific combining ability SCA, Heterosis, Fruit yield per plant, Pods per plant, Seed yield per plant, P1, P2 , F1, F2 , BC1, & BC2 , Depression, Dominance, Heritability, Genetic advance, Gene action, 100 seed weight, Water stress,|
|Subjects:||Agriculture & Veterinary Sciences(a)|
|Deposited By:||Mr Ghulam Murtaza|
|Deposited On:||16 Jun 2006|
|Last Modified:||04 Oct 2007 21:00|
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